Commit 14bc2414 authored Apr 19, 2016 by James Hogan Committed by Ralf Baechle May 13, 2016

MIPS: Fix HTW config on XPA kernel without LPA enabled



The hardware page table walker (HTW) configuration is broken on XPA
kernels where XPA couldn't be enabled (either nohtw or the hardware
doesn't support it). This is because the PWSize.PTEW field (PTE width)
was only set to 8 bytes (an extra shift of 1) in config_htw_params() if
PageGrain.ELPA (enable large physical addressing) is set. On an XPA
kernel though the size of PTEs is fixed at 8 bytes regardless of whether
XPA could actually be enabled.

Fix the initialisation of this field based on sizeof(pte_t) instead.

Fixes: c5b36783 ("MIPS: Add support for XPA.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Steven J. Hill <sjhill@realitydiluted.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13113/


Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

parent 12822570

arch/mips/mm/tlbex.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -2424,9 +2424,7 @@ static void config_htw_params(void)
		if (CONFIG_PGTABLE_LEVELS >= 3)
		pwsize \|= ilog2(PTRS_PER_PMD) << MIPS_PWSIZE_MDW_SHIFT;

		/* If XPA has been enabled, PTEs are 64-bit in size. */
		if (config_enabled(CONFIG_64BITS) \|\| (read_c0_pagegrain() & PG_ELPA))
		pwsize \|= 1;
		pwsize \|= ilog2(sizeof(pte_t)/4) << MIPS_PWSIZE_PTEW_SHIFT;

		write_c0_pwsize(pwsize);

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